On October 20, a power failure at Google Cloud's London region knocked out banking apps, delivery firms and courts across the UK.
One of Google's three London zones, europe-west2-b, lost power just after 7:00 a.m. UK time.
Thousands of Revolut customers could not open the app or pay with their cards in shops and at petrol stations.
Lloyds, HSBC, Barclays, Halifax, NatWest and Nationwide all reported access and payment problems.
The courts' video platform went down at 10:00 a.m. Trials and hearings across England and Wales could not proceed.
Delivery firms, the NHS app, Rightmove and Spotify also reported problems during the outage.
London is Google's only cloud region in the UK, so customers had nowhere else to move their work.
An administrator sharing Google's engineering update said backup generators failed to engage at first.
Google said the power event was mitigated by 12:27 p.m. Most workloads recovered by mid-afternoon.
Revolut confirmed that all customer money and data stayed safe, and services were restored by the evening.
The Ministry of Justice said court systems were still not fully restored by late afternoon.
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